Drafting mechanism



April 17, 1962 P. B. TARBOX DRAFTING MECHANISM Filed Oct. 6, 1960 3,029,479 DRAFTING MECHANISM Philip B. Tarbcx, Clemson, S.C., assignor to Sane-Lowell Shops, Boston, Mesa, a corporation of Maine Filed Oct. 6, 1960, Ser. No. 60,892 6 (Iiaims. (Cl. 19-251) This invention relates to drafting mechanisms of the type used on spinning and roving frames and the like, and more particularly to novel front roll positioning structures for the upper drafting elements of drafting mechanisms of the type wherein a short upper apron cooperates to perform the drafting function with a long lower apron having an apron supporting roll and apron bar within its loop.

In mechanisms of this type, the use of a cap bar supported front top roll is desirable because of the simple nature of the roll which may thereby be employed. More specifically, if a front top roll can be supported in cap bars by the use of arbors at its ends, rather than being supported centrally thereof between its bosses, a one piece roll structure may be employed wherein all anti-friction bearings are eliminated to produce not only a less expensive roll but a roll made more reliable as well by the elimination of bearing failures.

Heretofore, however, such a structure has been subject to at least two deficiencies. The first of these has to do with the manner of maintaining the front top roll in proper parallel alignment with its cooperating bottom roll, since, if the parallel relationship is disturbed to such an extent that the axis of the top roll and bottom roll no longer lie in a common plane, then the contact between the two rolls becomes shortened and the drafting operation becomes erratic and generally unsatisfactory. This problem is particularly troublesome in drafting mechanisms wherein cap bars are employed for cating the upper drafting elements, since the parallel relationship is lost as the cap bar bearing slots become worn with use.

The second deficiency of cap bar structures has to do with the piecing up operation wherein from time to time in the use of the spinning frame, a yarn breakage must be remedied by piecing together the broken ends of yarn. With the conventional cap bar structure, such is diflicult to accomplish because the cap bars prevent access to the apron fiber control mechanism, making it necessary to piece up at the front roll. But this is not entirely satisfactory since the speed of the front roll is 10 to times that of the apron control mechanism, so that great skill is necessary successfully to piece up a broken yarn.

Accordingly, the present invention is directed to a novel positioning and supporting structure for the front top roll of drafting elements of the short apron type so that alignment of the front top roll is readily maintained and piecing up may be accomplished at the apron fiber control mechanism.

It is a feature of the invention that the apparatus provided is readily adapted for use on spinning or roving frames having a long lower apron structure including a lower apron bar, such bar providing the alignment and support for the top rolls of the structure.

The nature of the invention will be readily understood from the following description when read in connection with the accompanying drawings and the novel features will be particularly pointed out in the appended claims.

In the drawings:

FIG. 1 is a view mainly in vertical section showing a drafting mechanism embodying a preferred embodiment of this invention; and

FIG. 2 is a plan view of the mechanism shown in FIG. 1.

Referring to the drawings, the drafting mechanism of Patented Apr. 17, 1962 the invention in general includes a pair of front or delivery rolls, an intermediate fiber control mechanism for feeding and controlling a strand of discontinuous fibers such as cotton, roving or sliver, and behind the fiber control mechanism, a pair of holding rolls. The fiber control mechanism itself includes, as a lower unit, an endless underlying fiber supporting lower apron 20 having within its loop a lower apron driving roll 22, an apron bar 24 forward of said apron driving roll and an apron tensioning roll 28 suitably mounted beneath said apron bar 24 and apron driving roll 22. Its upper unit includes an apron cradle having side members '40 and a tensor 42 extending therebetween, said cradle mounting and positioning an overlying roll 6. An overlying short apron 30 encircles said roll and tensor. The lower rolls, delivery roll 12, holding roll 16 and lower apron driving roll 22, extend for the entire length of the spinning frame and are driven by gearing located in the ends thereof.

The top rolls, front or delivery roll 4, overlying apron roll 6 and holding roll 8, are all generally similar, being of the type employing two bosses with a pair of cots or short aprons cooperating therewith, one of said cots or aprons encircling each boss of said roll and, in the case of the aprons, the tensor 42 as well, to cooperate with a pair of lower aprons 20 therebeneath. These rolls also include a permanent magnet housed therewithin which cooperates with the bottom roll of ferromagnetic material. This provides the necessary weighting of the drafting elements. More specifically, a preferred roll is that disclosed in application Serial No. 782,695, filed December 24, 1958, wherein the top roll comprises a shell of non-magnetic material which is adapted to receive a permanent magnet and the two end pieces which are adapted to be press-fitted into the cooperating end portions of the shell such that they abut the magnet. The end pieces have an arbor extending outwardly of the flange. With the front and rear top rolls 4 and 8, cots of synthetic material are snapped over the bosses and positioned on the shell. In the apron roll 6, the aprons encircle the bosses to drive the roll therethrough. With each top roll placed in a horizontal running position resting against a bottom roll, a flux path is created via the magnetic end pieces associated with the top roll between the pieces and the bottom roll and through the bottom roll. The bottom roll may also include permanent magnet materials therein and may act either in conjunction with a permanent magnetic top roll or not depending on the weighting and degree of driving force required.

Thus, the top delivery or front roll 4 includes pairs of bosses 14 and arbors 15 and the top holding roll 8 pairs of bosses 18 and arbors 19. The two bosses 34 of the top control roll 6 have arbors 36 which are positioned at each end thereof by suitable bearing recesses 44 in apron side cradle members 40. The short upper apron 30 overlies the lower apron 20 to cooperate therewith to control a strand as it passes between the aprons, both of the aprons being nipped to drive them between the apron driving roll 22 and the overlying upper roll bosses 34. The apron cradle includes side members 40 spaced to fit adjacent the sides of a boss 34 to limit lateral movement of the roll and an apron tensor 42 having a rounded forward apron engaging edge extends between said side members at the forward portion of the cradle inside the loop of upper apron 30, the tensor normally being positioned above apron bar 24 and being the sole transverse structural member extending between said side pieces. The cradle together with boss 34 on said overlying roll supports and guides the upper apron 30, the side members of the cradle also functioning to guide the apron 30 to prevent lateral movement thereof with respect to the cradle. The recesses 44 provided on the rear edge of said members 40 engage the arbors 36 of the upper roll while the apron 30, encircling a boss 34 and a tensor 42, firmly but removably holds the cradle and roll together, maintaining them in a normal assembled relation both on and off the frame.

The apron cradle is supported and aligned by apron bar locating means. Thus, legs 46 are provided on each side member 40, such legs being spaced outwardly from the inner surface of said side members to provide lateral clearance for both the upper and lower aprons. The legs 46 extend downwardly from said side members and are received in a pair of cooperating recesses 26 in the rear face of apron bar 24 to provide an accurately determined and fixed lateral position of the cradle relative to the apron bar while at the same time permitting the cradle to be removed simply by lifting it backwardly and upwardly with apron 30 and the upper roll 6. To support the forward end of the cradle and make it self-spacing to provide an accurate vertical clearance between the tensor and lower apron bar 24, a suitable means such as a machine screw 49 is mounted on the apron bar between the roll bosses with the head thereof extending upwardly.

The present invention concerns a novel front top roll mounting structure and is an improvement over that shown and described in application Serial No. 828,247, filed July 20, 1959. In that application, the arbors on the end of the front roll were mounted in bearing members which were in turn mounted on the apron bar. Such structure, however, although satisfactory from the standpoint of front roll alignment, was difficult to piece up because such had to be done at the front roll.

According to the present invention, piecing up at the apron fiber control mechanism is made possible by supporting the front roll arbors by means mounted on the cradle tensor generally centrally thereof between the upper aprons and extending laterally across the bosses of the front roll and the apron roll.

More specifically, as is best seen in FIGURE 2, the front roll support means includes a pair of generally U-shaped members generally designated 50, each being rigidly mounted on the apron tensor 42 generally centrally thereof between bosses 34, in side by side relationship but spaced as far as possible from one another for optimum alignment, by means of suitable screws 53 in inwardly extending lugs 52 at the free end of the inner leg 54 of said U-shaped member 50. The free end of the outer leg 58 of said U-shaped member 50 is provided with a bearing recess 60 open at its upper side to receive the arbor 15 of the front roll 4. Preferably, an end wall 62 is provided at the outer end of bearing recess 60 lateral- 1y to position front roll 4 by contact of the ends of its arbors 15 with the inner surfaces of said walls.

The connecting base portion 64 of each of said supporting members 50 extends perpendicularly to legs 54 and 58 therebetween and laterally between the overlying apron roll 6 and the front roll 4 generally parallel thereto. However, by reason of the legs 54 and 58 thereof extending outwardly and upwardly relatively to the axes of the front top roll 4 and tensor 42, such base portion 64 is positioned well outside of and spaced from the plane of the axes of the front and apron top rolls, generally in a plane tangent to the upper surfaces of said rolls so that such rolls may be as close together as may be desired for fiber control. The legs 54 and 58 are at an acute angle to one another, herein shown as about 60 degrees, to position base portion 64 generally midway between the two rolls 4 and 6 so that it may be close thereto, as is desirable. Preferably the pair of support members 50 are interconnected by a cylindrical reinforcement rod 66 extending along, between and through the base portions 64 of said members 50 therebetween generally in the tangent plane midway between the rolls 4 and 6. The members 50 themselves are preferably of magnetically insulating material, such as nylon, so that an undesired flux path will not be provided, as well as to provide a suitable bearing for arbors 15.

With the above structure utilizing magnetic weighting as is preferred, the overlying apron roll 6, aprons 30 and tensor 42 are removably positioned solely with reference to the apron bar 24 and by contact of the overlying apron roll 6 with the underlying apron driving roll 22 through the aprons. In turn, the front top roll 4 is positioned with reference to the tensor 42 and by contact of said front top roll with its underlying bottom roll 12. Thus, the front top roll 4 as well as the overlying apron roll 6 is positioned solely with reference to the apron bar and the underlying rolls, with the overlying apron roll 6 and front roll 4 being positively maintained parallel to one another by virtue of the mounting of the front top roll arbors on the apron tensor 42 which also, through the cradle side members 40, mounts the overlying apron roll 6.

With the magnetically weighted structure as above described an extraordinarily simple and effective drafting mechanism is provided and one which may be pieced up around the end of the front roll without the necessity of piecing up at said front roll with its attendant difiicuities.

if desired, the front roll may readily be removed either by itself or with the entire upper apron assembly which may easily be lifted out of the frame to facilitate cleaning or changing of aprons without stopping other por tions of the spinning frame. The aprons, cradles and their overlying rolls, comprising the upper apron assembly, may be taken apart by first tightening aprons 313 sufficiently to allow arbors 36 to be sprung out of recesses 44, then sliding both the cradle and the aprons lengthwise of the upper roll over the bosses 34 to remove the aprons 3i and cradle from the roll and finally sliding the cradle out of the loop of the aprons. The assembly is put together in reverse, the tension of the aprons alone serving to hold it together. The front roll if removed is simply dropped in its bearing elements to form a unitary assembly with the upper apron assembly which may then be put back into the frame by positioning it relatively to the apron bar so that its legs engage the recesses therein.

Thus it will be seen that the invention provides a novel front top roll cooperating with a short upper apron assembly to make possible piecing up around the ends of the front rolls. Various modifications of the invention within the spirit thereof and the scope of the appended claims will be apparent to those skilled in this art.

I claim:

1. A drafting mechanism of the character described including a plurality of sets of devices for feeding and controlling a strand of discontinuous fibers, said sets being arranged one in advance of the other to act successively on a strand, the front set of said devices comprising a bottom roll and an overlying top roll having a pair of axially spaced bosses with arbors on the ends of said top roll beyond said bosses and another set of said devices rearwardly thereof comprising a pair of endless underlying strand supporting lower aprons each having within its loop a lower apron driving roll, an apron bar forward of said apron driving roll and an apron tensioning roll below said apron driving roll, and a pair of endless overlying aprons mounted above and contacting said lower aprons and having within their loops an overlying apron roll having pairs of spaced bosses and an apron cradle assembly including a tensor member forward of said overlying apron roll extending throughout the length of said roll between said spaced upper aprons, said overlying roll and said cradle tensor member being mounted at their ends on cradle side members, front roll support means mounted rigidly on said cradle tensor member generally centrally thereof between said upper aprons and extending laterally beyond the bosses of said front roll and having bearing means at its ends for receiving the arbors of said front top roll to removably position said front top roll solely with reference to said tensor and by contact of said front top roll with its underlying bottom roll.

2. A drafting mechanism as claimed in claim 1, wherein the portion of said front roll support means extending laterally between the bosses of said overlying apron roll and said front top roll is positioned spaced from the plane of the axes of said rolls adjacent a plane tangent to the upper surfaces of said rolls.

3. A drafting mechanism as claimed in claim 2 wherein said front roll support means has inner and outer leg means extending perpendicularly to said portion respectively to said tensor member and to said bearing means, said inner and outer leg means being at an acute angle to one another.

4. A drafting mechanism as claimed in claim 3 wherein said inner leg means has spaced mounting means on said tensor member.

5. A drafting mechanism of the character described including a plurality of sets of devices for feeding and controlling a strand of discontinuous fibers, said sets being arranged one in advance of the other to act successively on a strand, the front set of said devices comprising a bottom roll and an overlying top roll having a pair of axially spaced bosses with arbors on the ends of said top roll beyond said bosses and another set of said devices rearwardly thereof comprising a pair of endless underlying strand supporting lower aprons each having within its loop a lower apron driving roll, an apron bar forward of said apron driving roll and an apron tensioning roll below said apron driving roll, and a pair of endless overlying aprons mounted above and contacting said lower aprons and having within their loops an overlying apron roll having pairs of spaced bosses and an apron cradle assembly including a tensor member forward of said overlying apron roll extending throughout the length of said roll and between said spaced upper aprons, said overlying apron roll and said cradle tensor member being mounted at their ends on cradle side members and with said apron cradle assembly providing laterally spaced projections for engaging cooperating laterally spaced recesses on said apron bar, front roll support means mounted rigidly on said cradle tensor member generally centrally thereof between said upper aprons, said front roll support means extending laterally between said overlying apron roll and said front top roll generally parallel to said overlying apron roll and front roll beyond the bosses thereof and having bearing means at its ends for receiving the arbors of said front top roll removably to position said overlying apron roll, aprons and tensor solely with reference to said apron bar and by contact of said overlying apron roll with said underlying apron driving roll through said aprons, and to position said front top roll solely with reference to said apron bar and by contact of said front top roll with its underlying bottom roll.

6. A drafting mechanism of the character described including front, middle and rear sets of devices for feeding and controlling a strand of discontinuous fibers, said sets being arranged one in advance of the other to act successively on a strand, the front set of said devices comprising a bottom roll and an overlying top roll having a pair of axially spaced bosses with arbors on the ends of said top roll beyond said bosses and the middle set of said devices comprising a pair of endless underlying strand supporting lower aprons each having within its loop a lower apron driving roll, an apron bar forward of said apron driving roll and an apron tensioning roll below said apron driving roll, and a pair of endless overlying aprons mounted above and contacting said lower aprons and having within their loops an overlying apron roll having pairs of spaced bosses and an apron cradle assembly including a tensor member forward of said overlying apron roll extending throughout the length of said roll and between said spaced upper aprons, said overlying apron roll and said cradle tensor member being mounted at their ends on cradle side members and with said apron cradle assembly providing laterally spaced projections for engaging cooperating laterally spaced recesses on said apron bar, a pair of U-shaped front roll support members having inner and outer legs, said members being mounted rigidly on said tensor generally centrally thereof between said upper aprons with the inner legs of said U-shaped members mounted on said bar spaced from one another and adjacent said bosses, the base portions of said members extending laterally between said overlying apron roll and said front top roll generally parallel to said overlying apron roll and front roll generally in a plane tangent to said rolls beyond the bosses thereof, with the outer legs of said U-shaped members including closed end bearing means at their ends for receiving and positioning the arbors of said front top roll, with said inner and outer legs at an acute angle to one another and with an interconnecting element between said base portions in said plane, removably to position said overlying middle roll, aprons and tensor solely with reference to said apron bar and by contact of said overlying middle roll with said underlying middle roll through said aprons and to position said front top roll solely with reference to said apron bar and by contact of said front top roll with its underlying bottom roll.

No references cited. 

